Swimming Pools & Aquatic Centers

Pool Ventilation: Controlling Chloramines and Corrosion

In pool halls and technical rooms, chlorine, humidity, and heat combine into a mix that degrades air quality and corrodes equipment. Undersized ventilation is costly on both fronts: occupant health and equipment lifespan.

Chloramines: A Documented Health Risk

Combined chlorine, mainly trichloramine (NCl₃), forms when chlorine reacts with organic matter brought in by swimmers (sweat, urine, cosmetic products). Heavier than air, it settles near the water surface and produces the characteristic chlorine smell, irritating to the respiratory tract and eyes.

French health authority ANSES sets an alert threshold of 0.3 mg/m³ in pool hall air, a level frequently exceeded in poorly ventilated facilities. Lifeguards and maintenance staff, exposed for hours at a time, are most affected. This exposure risk must be documented in occupational risk assessments.

In France, the regulatory framework rests on the amended decree of April 7, 1981 setting technical requirements for pools, and the decree of September 14, 2004 for privately operated collective pools. Regional health authorities (ARS) enforce these rules and can order pool closures when chloramine levels are significantly exceeded.

Ventilation Sized to Precise Rules

Beyond health thresholds, a few sizing principles come up consistently in the technical literature:

• 🌬️ An extraction rate around 60 m³/h per bather in the pool hall (French guidance)
• 🌡️ A maximum 2°C gap between air and water temperature, to limit evaporation and chloramine formation
• ⚗️ Negative pressure in the chemical storage room, isolated from the rest of the building (ASHRAE recommendation)

These principles apply equally to the pool hall and to adjacent technical spaces: chlorine storage rooms, dosing cabinets, and buffer tanks, where gas concentrations are highest.

Corrosion: A Hidden Cost for Operators

Chlorine gas and ambient humidity progressively attack any exposed metal parts: housing corrosion, bearing seizure, degraded electrical connections. A pool facility runs for thousands of hours a year on average, exposing technical equipment continuously to the room's corrosive conditions. A fan that corrodes prematurely means a costly replacement cycle, not to mention operational downtime.

Our Polypropylene Fans for Pool Facilities

SEAT Ventilation designs and manufactures polypropylene fans with no metal parts exposed to the airstream. This design makes them naturally suited to the corrosive environments of pool facilities: high chlorine concentrations, caustic or acidic products, and high humidity levels.

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